Roommate expense calculator
Shared living means dozens of small payments a month. Log them as they happen and settle once, without anyone keeping a mental scoreboard.
Short answer
Add every recurring bill under the name of whoever's direct debit it comes out of, then split each one by usage or equally, and settle the net difference once a month rather than after every bill.
People
Expenses
Balances
- Alex$375.00
- Sarah$15.00
- Mike$165.00
- Emma$195.00
+ gets money back · − owes money
💸 Settle up
Only 3 payments needed.
- EmmaAlex$195.00
- MikeAlex$165.00
- SarahAlex$15.00
Who paid what
- Alex$600.00
- Sarah$180.00
- Mike$60.00
Saved on this device. No account needed.
How it works
- 1Add every roommate once — the group is saved on your device.
- 2Log rent, utilities, groceries and household items as they are paid.
- 3Exclude anyone who was away for a shared cost that did not benefit them.
- 4Settle up at the end of the month and start a fresh group.
Roommates rarely pay bills in step. One person's bank account holds the broadband direct debit, another's holds the electricity, and rent might come out of a joint account entirely. The fix isn't to reroute every bill through one account — it's to log who actually paid each one and let the maths net it out.
Treat the household as a running ledger rather than settling bill by bill. Add rent, electricity, water, broadband and council tax as separate line items each month, tick who paid, and let unequal splits (like a bigger single room) sit on top of the equal ones.
Settling once a month, rather than reimbursing each bill separately, cuts a house of four from a dozen small transfers down to one or two.
Worked examples with real numbers
Three flatmates, four monthly bills
Priya, Sam and Ola share a flat. Priya's account pays rent (900) and electricity (60). Sam's account pays broadband (40). Ola's account pays water (30). All bills are split equally three ways.
| Who paid what | Amount |
|---|---|
| RentPriya's account | 900.00 |
| ElectricityPriya's account | 60.00 |
| BroadbandSam's account | 40.00 |
| WaterOla's account | 30.00 |
| Total | 1,030.00 |
| Person | Paid | Fair share | Balance |
|---|---|---|---|
| Priya | 960.00 | 343.33 | +616.67 |
| Sam | 40.00 | 343.33 | −303.33 |
| Ola | 30.00 | 343.34 | −313.34 |
- SamPriya303.33
- OlaPriya313.34
Priya fronted 960 of the 1030 total and only owes 343.33 herself, so both flatmates pay her directly — no need to also settle between Sam and Ola.
Fourth roommate with a bigger room
Add a fourth flatmate, Dee, who has the largest bedroom and agrees to pay 10% more of rent than an equal split, with bills still shared equally. Rent is 1200 total: Priya, Sam and Ola pay 360 each and Dee pays 396. Electricity (80), broadband (40) and water (30) stay equal at 37.50 each.
| Rent share vs equal bills | Amount |
|---|---|
| RentTotal, paid by Priya | 1,200.00 |
| ElectricityPaid by Priya | 80.00 |
| BroadbandPaid by Sam | 40.00 |
| WaterPaid by Ola | 30.00 |
| Total | 1,350.00 |
| Person | Paid | Fair share | Balance |
|---|---|---|---|
| Priya | 1,280.00 | 327.50 | +952.50 |
| Sam | 40.00 | 327.50 | −287.50 |
| Ola | 30.00 | 327.50 | −297.50 |
| Dee | 0.00 | 367.50 | −367.50 |
- DeePriya367.50
- SamPriya287.50
- OlaPriya297.50
Weighting only the rent line — not the bills — keeps the arithmetic transparent: rent splits 290/290/290/330 (Dee pays 40 extra for the bigger room) while all three bills still split evenly at 37.50 each.
How the monthly net works
1. Total spend
sum of all bills entered, regardless of who paid
2. Fair share per bill
bill amount ÷ number of people it applies to (equal), or a custom split if agreed
3. Person's total share
sum of their fair share across every bill
4. Balance
amount paid − total share
positive means owed money, negative means owes money
5. Settlement
largest debtor pays largest creditor first, repeated until every balance is zero
Mistakes that cause arguments
Settling bill by bill
Reimbursing rent separately from electricity separately from broadband multiplies the number of transfers for no benefit — net it all at month end instead.
Ignoring who's actually on the direct debit
If bills auto-renew under one person's bank account, that's a real prepayment and belongs in the ledger even though no cash changed hands between roommates yet.
Forgetting one-off shared costs
A replacement router or a cleaner booked for move-out is still a household expense — add it as its own line rather than folding it into a regular bill.
Practical tips
- Log bills as soon as they're paid, not at the end of the month, so nobody forgets a smaller one like water.
- Give someone with a bigger room or private bathroom a heavier rent split while keeping bills equal — don't apply the weighting everywhere.
- Agree a settle-up day (payday works well) so the ledger never runs longer than a month.
- If someone moves out mid-month, prorate their share by days lived there rather than dropping them from that month entirely.
Questions
- Can rooms with different rents be handled?
- Yes. Split the rent expense with custom amounts so each room pays its own figure.
- What about a roommate who was away for a month?
- Untick them on the groceries and utilities for that period; keep them on rent if they still owe it.
- Do I have to re-enter everyone each month?
- No. The group persists in your browser until you clear it.